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61.
黑土水稳性团聚体测定方法研究 总被引:9,自引:0,他引:9
研究不同浸润方式、浸润时间和浸提剂对黑土水稳性团聚体总量和在各粒级间分布的影响,以及砾石对水稳性团聚体含量的贡献率。结果表明:非真空慢速浸润方式最适合黑土团聚体的测定;团聚体含量随浸润时间变化不显著;蒸馏水比自来水浸提出更多的团聚体;乙醇溶液对有机质含量较高的黑土保护作用不显著;黑土砾石含量较少,对团聚体含量的构成可以忽略。表4,参10。 相似文献
62.
通过对太白山自助旅游者问卷调查,运用旅游地理学、行为地理学及比较分析等方法,探讨了太白山自助旅游者的行为特征和生态旅游意识.结果表明,自助旅游者倾向于选择生态保护好的旅游目的地,且多为自发组织或通过卢外运动俱乐部带领并偏好小规模的团队;自助旅游者对景区线路的选择以点对点线路为主,表现为单一的目的地选择;对弹性比较大的旅行设备表现出强烈的购买欲望,但景区内消费较低;出游时间更倾向于避开旅游高峰期,即选择淡季出游;自助旅游者的环保意识较强,属于比较严格的生态旅游者。 相似文献
63.
《Journal of Natural History》2012,46(17):1367-1380
The parasitic wasp Trogus pennator (Ichneumonidae) attacks the larvae of swallowtail butterflies (Papilionidae). Female T. pennator were followed in the field as they searched for larvae of the zebra swallowtail butterfly, Eurytides marcellus (Papilionidae), feeding on Asimina (Annonaceae) in central Florida, USA. Predictions of host‐finding theory and interactions with the host were thus investigated in a natural setting. Wasps seldom flew to plants other than Asimina and apparently recognized the plants by visual cues. Plants were attractive regardless of host presence, as the wasps approached plants lacking E. marcellus feeding damage twice as often as they approached damaged plants. However, wasps approached damaged plants at a rate greater than their frequency in the Asimina population, indicating that they can detect host damage before they approach the plants. After approaching within 0.5?m of plants, wasps tended not to land on plants lacking feeding damage. A comparison of the plants they landed on, however, showed no consistent preferences for damaged plants. The weaker trends in the latter data indicate that the presence of feeding damage was not the sole criterion for landing, although it evidently influenced behaviour. After landing, wasps spent more time searching damaged plants than undamaged plants. Butterflies preferred to oviposit on plants shorter than those searched by T. pennator. Possible adaptive consequences of this phenomenon are discussed. 相似文献
64.
研究了添加有机粘结剂G对制粒过程的影响.结果表明,添加有机粘结剂G使水在矿粉颗粒表面的润湿角降低,提高了矿粉的亲水性,强化了制粒过程;似粒子内部颗粒间受力分析表明,由于润湿角的降低使作用在润湿周边的界面张力以及毛细作用力增大,从而提高了似粒子的强度 相似文献
65.
《Journal of Natural History》2012,46(32):3013-3027
Male Mannophryne trinitatis transport their larvae on their backs to predator‐free pools and deposit them there. The experiments reported here investigated M. trinitatis male deposition behaviour in containers placed near a heavily fish‐populated stream at Mount Saint Benedict, northern Trinidad. Choice of deposition site was not related to height above or distance from the stream. The low mean number of tadpoles deposited in each container in the field and in a laboratory experiment indicated that most males tended not to deposit complete clutches in single pools. Deposition experiments in the laboratory with a choice of different‐sized containers showed that deposition was pool size dependent, with more tadpoles deposited in larger containers. Deposition behaviour when given a choice of containers with leaf litter (a source of food and shelter) and with no leaf litter showed no significant preference. Tadpoles grown in different water volumes with different food sources revealed that tadpole growth was best in larger water volumes containing leaf litter. Regular tadpole inspections at a pool in the field established that most tadpoles present were the result of downstream movement. 相似文献
66.
傅小勇 《中山大学学报(自然科学版)》1997,36(6):44-48
对按曲线流γt=V(θ,k)N演化着的平面光滑简单闭凸曲线给出了1个等周估计.由此结合尺度论证法得到平面光滑简单闭凸曲线在上述曲线流下的渐近性态. 相似文献
67.
介绍了利用图象处理技术研究了Sn-Pb合金钱民铜润湿性的方法,提出了联机的图象特征提出算法和润湿参数求取算法,给出了Sn-Pb/Cu润湿特性在直流电影响下测试分析结果。 相似文献
68.
微结构疏水表面的液滴浸润特性 总被引:1,自引:1,他引:0
以聚二甲基硅氧烷(PDMS)为基底采用光刻蚀法制备了具有不同粗糙度的微方柱结构疏水表面,研究了微结构疏水表面的液滴浸润特性.结果表明,微方柱高度对表观接触角影响很小,但会显著影响疏水表面液滴浸润状态的稳定性,当微方柱边长和间距一定时,存在一个临界高度,当微方柱高度大于该临界值时,液滴具有良好的稳定性.通过对不同温度下疏水表面液滴浸润状态的研究表明,在露点温度至环境温度区间内,随着温度的增加,表观接触角呈增大趋势;在环境温度至沸点温度区间内,随着温度的升高,表观接触角呈减小的趋势.研究认为,合理的微结构尺寸和应用环境温度对液滴浸润状态的稳定具有重要意义. 相似文献
69.
《Journal of Natural History》2012,46(19-20):1169-1179
The homing ability of the rock pool blenny Parablennius parvicornis was studied at a rocky shore on Gran Canaria (Canary Islands, Spain). A total of 140 fish was tagged in five different rock pools and 100 of these were displaced from their original site, during low tide. This blenny species shows great site fidelity and is able to return home from 400 m away. Results show that homing success mainly depends on the displacement distance and it increases when fish return against the current, whereas sex and fish size have no influence. 相似文献
70.
对智能复合材料在经受单向拉-拉试验产生的光纤疲劳失效性能进行了研究,对智能复合材料内的光纤方位角分别为0°,45°,90°进行了应力-寿命试验,在输入应变能量的基础上提出了疲劳失效准则,这一准则可用于光纤方位角的调整和应力比的分析。 相似文献